Adrenal masses are nowadays more and more diagnosed incidentally. In the vast majority of cases these "incidentalomas" are benign adrenocortical adenomas which do not compel operative therapy. In about 12% of patients an endocrine activity is detected. With Increasing tumor size the risk of malignancy increases. This article summarizes recommendations, only to allow patients with endocrine activity or an increased risk of malignancy to be selected for surgery. A small uncertainty will always remain, but may be minimized by an individually tailored follow-up.